PROJECT SUMMARY This application requests funding to purchase a General Electric Healthcare SPINlab? Carbon-13 (C13) polarizer needed to expand our molecular imaging capability by initiating a new hyperpolarized carbon-13 (HP-C13) metabolic imaging program. This state-of-the-art C13 polarizer is the only dynamic nuclear polarizer capable of producing large amounts of HP-C13 substrates suitable for animals of various sizes, and the only one equipped with sterile operations for potential clinical applications. Two nearest SPINlab systems are located 210 miles away in New York. Thus the proposed C13 polarizer will be an invaluable resource for the rich body of bi-directional translational research at the Martinos Center and the larger MGH research community, as well as at other institutions in New England. Providing more than a 10,000-fold increase in signal-to-noise ratio (SNR) compared to thermal equilibrium 13C nuclei, hyperpolarized MR spectroscopic imaging (MRSI) forms an important bridge between MRI and molecular imaging. Metabolic MRSI using HP-C13 substrates allows objective measures of the injected substrate and its metabolic products to track key metabolic pathways, a novel imaging technique for dynamic in vivo detection of metabolism in enzyme-catalyzed reactions. The potential of HP-C13 metabolic imaging has been demonstrated in preclinical studies of a range of diseases, as well as in clinical trials of prostate cancer patients. The proposed polarizer will enable sophisticated metabolic imaging studies of cancer, traumatic brain injury, and heart diseases, by our users, while ensuring the successful development of this promising technique for years to come. The proposed C13 polarizer will be located within the MGH Martinos Center for Biomedical Imaging, which operates as a NCRR-funded National Research Resource, supplying state-of- the-art molecular imaging instrumentation and services to MGH and the broader research community nationwide. The Martinos Center has a renowned molecular imaging program, consistently producing successes with every new modality that has been incorporated into our program, such as MEG, PET, Nano-particle MRI and Optical Imaging. With the same rigor and dedication, we anticipate the successful development of a new HP-C13 metabolic imaging program. The proposed instrument will be used with the existing PET-MR systems for HP-C13 metabolic imaging research. Therefore, by offering the usage of the proposed C13 polarizer to researchers across New England, we are also sharing our advanced pre-clinical and clinical MRI as well as PET resources to our users throughout the region.